enricobuehler
58ccd530fc
ffmpeg-sys-next binds a curated header list that omits every hwcontext_*.h, so AVVulkanDeviceContext/AVVulkanFramesContext/AVVkFrame — the surface that lets FFmpeg's Vulkan Video decoder run on the presenter's own VkDevice and hand the decoded VkImages back — had no Rust bindings at all. pf-ffvk generates them at build time from the SYSTEM headers, which is the only ABI-safe option: the struct layout depends on FF_API_* deprecation gates resolved in libavutil/version.h (confirmed: FFmpeg 8.1 still carries the FIXED_QUEUES fields). Ships ash<->vulkan.h handle conversions; opaque AVHW*/AVFrame types keep ffmpeg-sys-next the owner of the core surface (pointer casts across). Needs vulkan-headers (Arch) / libvulkan-dev (CI, added); PF_FFVK_VULKAN_INCLUDE overrides for cross builds. Verified: bindgen layout tests pass, av_vk_frame_alloc links and zero-initializes. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
76 lines
3.4 KiB
Rust
76 lines
3.4 KiB
Rust
//! Generate bindings for `libavutil/hwcontext_vulkan.h` against the SYSTEM headers.
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//!
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//! ffmpeg-sys-next binds a curated header list that omits every hwcontext_*.h; the
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//! Vulkan hwcontext structs (`AVVulkanDeviceContext`, `AVVkFrame`) are what let us run
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//! FFmpeg's Vulkan Video decoder on the presenter's own VkDevice and read the decoded
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//! VkImages back. Their layout depends on compile-time FF_API_* deprecation gates in
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//! libavutil/version.h, so bindgen over the installed header is the only ABI-safe
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//! source of truth — hand transcription would silently skew on the next FFmpeg bump.
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//!
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//! Non-Linux targets get an empty file: the workspace builds on macOS (clients/apple is
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//! the client there), and this shim is Linux-client plumbing only.
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use std::env;
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use std::path::PathBuf;
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fn main() {
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println!("cargo:rerun-if-changed=wrapper.h");
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let out = PathBuf::from(env::var("OUT_DIR").unwrap()).join("bindings.rs");
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if env::var("CARGO_CFG_TARGET_OS").as_deref() != Ok("linux") {
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std::fs::write(&out, "// pf-ffvk: Linux-only, empty on this target\n").unwrap();
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return;
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}
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// Include paths from pkg-config (libavutil for the hwcontext header; the Vulkan
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// headers usually live in /usr/include, but honor a registered vulkan.pc too).
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// PF_FFVK_VULKAN_INCLUDE prepends an explicit Vulkan-Headers include dir — for
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// cross builds and boxes without the system package.
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println!("cargo:rerun-if-env-changed=PF_FFVK_VULKAN_INCLUDE");
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let mut includes: Vec<PathBuf> = Vec::new();
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if let Ok(dir) = env::var("PF_FFVK_VULKAN_INCLUDE") {
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includes.push(PathBuf::from(dir));
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}
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let avutil = pkg_config::Config::new()
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.cargo_metadata(false)
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.probe("libavutil")
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.expect("pkg-config: libavutil not found — install the FFmpeg dev package");
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includes.extend(avutil.include_paths);
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if let Ok(vk) = pkg_config::Config::new()
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.cargo_metadata(false)
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.probe("vulkan")
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{
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includes.extend(vk.include_paths);
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}
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let mut builder = bindgen::Builder::default()
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.header("wrapper.h")
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// The whole point of this crate: the Vulkan hwcontext surface…
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.allowlist_type("AVVulkan.*")
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.allowlist_type("AVVkFrame.*")
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.allowlist_function("av_vk_frame_alloc")
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.allowlist_function("av_vkfmt_from_pixfmt")
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// …plus nothing else of FFmpeg: the core types these structs reference only
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// ever appear behind pointers here, so keep them opaque instead of duplicating
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// ffmpeg-sys-next's definitions (callers cast pointers between the crates).
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.opaque_type("AVHWDeviceContext")
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.opaque_type("AVHWFramesContext")
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.opaque_type("AVBufferRef")
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.opaque_type("AVFrame")
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.derive_debug(false)
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.layout_tests(true);
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for dir in &includes {
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builder = builder.clang_arg(format!("-I{}", dir.display()));
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}
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let bindings = builder.generate().expect(
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"bindgen over libavutil/hwcontext_vulkan.h failed — is `vulkan-headers` installed? \
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(the header includes <vulkan/vulkan.h>)",
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);
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bindings.write_to_file(&out).unwrap();
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// The av_vk_* symbols live in libavutil, which ffmpeg-sys-next already links into
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// every consumer of this crate; no extra link flags needed. Emitting the lib anyway
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// keeps `cargo test -p pf-ffvk` linking standalone.
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println!("cargo:rustc-link-lib=avutil");
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}
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